public class Text {
    public static void main(String[] args) {
        int a = 10;
        int b = 20;
        swap(a,b);
        System.out.println("swap: a = " + a + ", b = " + b);
    }
    public static void swap(int x, int y) {
        int tmp = x;
        x = y;
        y = tmp;
        System.out.println("swap: x = " + x + ", y = " + y);
    }
}
